Sukhorukov B I, Montrel' M M
Institute of Biological Physics, Academy of Sciences of the U.S.S.R., Pushchino, Moscow Region.
Biophys Chem. 1990 Jan;35(1):47-54. doi: 10.1016/0301-4622(90)80059-g.
The influence of H+ on the secondary structure of DNA and on its B-to-A transition has been studied by employing X-ray diffraction and infrared spectroscopy. Helical parameters for DNA molecules with different degrees of protonation were determined. It was shown that H+ binding stabilizes the B-form of DNA in fibers over a wide range of water and inorganic salt content. Only 0.03 H+ bound per nucleotide is sufficient to prevent the B-to-A transition caused by decreasing relative humidity in DNA fibers containing 4% NaCl. The effectiveness of B-form stabilization by H+ is explained by changes in DNA-solvent molecule interactions, especially in the major groove of double helices.
通过X射线衍射和红外光谱研究了H⁺对DNA二级结构及其B型向A型转变的影响。测定了不同质子化程度的DNA分子的螺旋参数。结果表明，在较宽的水和无机盐含量范围内，H⁺结合可稳定纤维状DNA的B型结构。在含有4%氯化钠的DNA纤维中，每个核苷酸仅结合0.03个H⁺就足以防止因相对湿度降低而导致的B型向A型转变。H⁺对B型结构的稳定作用是通过DNA与溶剂分子相互作用的变化来解释的，尤其是在双螺旋的大沟中。
